Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
/*
 *created by Kraken on 03-05-2020 at 16:00
 */
//package com.kraken.cf.practice;

import java.util.*;
import java.io.*;

public class A815 {

  private static int[] rrow, rcol, crow, ccol;
  private static int n, m;

  private static long findRow(int[][] mat) {
    rrow = new int[n];
    rcol = new int[m];
    for (int i = 0; i < n; i++) {
      int min = Integer.MAX_VALUE;
      for (int j = 0; j < m; j++) min = Math.min(min, mat[i][j]);
      rrow[i] = min;
    }
    for (int j = 0; j < m; j++) {
      int min = Integer.MAX_VALUE;
      for (int i = 0; i < n; i++) min = Math.min(min, mat[i][j] - rrow[i]);
      rcol[j] = min;
    }
    boolean fine = true;
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        if (mat[i][j] != rrow[i] + rcol[j]) {
          fine = false;
          break;
        }
      }
      if (!fine) break;
    }
    if (!fine) {
      return -1;
    }
    long cnt = 0;
    for (int i : rrow) cnt += i;
    for (int i : rcol) cnt += i;
    return cnt;
  }

  private static long findCol(int[][] mat) {
    crow = new int[n];
    ccol = new int[m];
    for (int j = 0; j < m; j++) {
      int min = Integer.MAX_VALUE;
      for (int i = 0; i < n; i++) min = Math.min(min, mat[i][j]);
      ccol[j] = min;
    }
    for (int i = 0; i < n; i++) {
      int min = Integer.MAX_VALUE;
      for (int j = 0; j < m; j++) min = Math.min(min, mat[i][j] - ccol[j]);
      crow[i] = min;
    }
    boolean fine = true;
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        if (mat[i][j] != crow[i] + ccol[j]) {
          fine = false;
          break;
        }
      }
      if (!fine) break;
    }
    if (!fine) {
      return -1;
    }
    long cnt = 0;
    for (int i : crow) cnt += i;
    for (int i : ccol) cnt += i;
    return cnt;

  }

  private static String findAns(int[] row, int[] col, long cnt) {
    StringBuilder sb = new StringBuilder();
    sb.append(cnt).append("\n");
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < row[i]; j++)
        sb.append("row ").append(i + 1).append("\n");
    }
    for (int i = 0; i < m; i++) {
      for (int j = 0; j < col[i]; j++)
        sb.append("col ").append(i + 1).append("\n");
    }
    return sb.toString();
  }

  public static void main(String[] args) {
    FastReader sc = new FastReader();
    n = sc.nextInt();
    m = sc.nextInt();
    int[][] mat = new int[n][m];
    for (int i = 0; i < n; i++) for (int j = 0; j < m; j++) {
      mat[i][j] = sc.nextInt();
    }
    long r = findRow(mat);
    long c = findCol(mat);
    if (r == -1 || c == -1) {
      System.out.println(-1);
      return;
    }
    if (r < c) {
      System.out.print(findAns(rrow, rcol, r));
    } else {
      System.out.print(findAns(crow, ccol, c));
    }
  }

  static class FastReader {

    BufferedReader br;

    StringTokenizer st;

    public FastReader() {
      br = new BufferedReader(new InputStreamReader(System.in));
    }

    String next() {
      while (st == null || !st.hasMoreElements()) {
        try {
          st = new StringTokenizer(br.readLine());
        }
        catch (IOException e) {
          e.printStackTrace();
        }
      }
      return st.nextToken();
    }

    int nextInt() {
      return Integer.parseInt(next());
    }

    long nextLong() {
      return Long.parseLong(next());
    }

    double nextDouble() {
      return Double.parseDouble(next());
    }

    String nextLine() {
      String str = "";
      try {
        str = br.readLine();
      }
      catch (IOException e) {
        e.printStackTrace();
      }
      return str;
    }
  }
}